woven structure Project in ms - word

Created By – Rizwan Rajik Qureshi

Project Report
On
Submitted by
Mr. Aniket G. Gajjalwar
(Bachelor of Textile Science, III Year)
Under the Guidance of
Mrs. Snehal Rohadkar
A Dissertation Submitted to R.T.M. Nagpur University
In Partial Fulfilment of the Requirement
For the Award of Degree Of
BACHELOR OF TEXTILE SCIENCE
MAHALAXMI JAGDAMBA COLLAGE OF LIBRARY & INFORMATION SCEINCE
RASHTRASANT TUKDOJI MAHARAJ NAGPUR UNVIVERSITY,
NAGPUR.2018-2019
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This is Certify that the dissertation entitled
Is a record of dissertation work
Carried out by
Submitted in the partial fulfilment of requirement
For the degree of Bachelor of Textile Science
Of R.T.M. Nagpur university.
MAHALAXMI JAGDAMBA COLLAGE OF LIBRARY & INFORMATION SCEINCE
RASHTRASANT TUKDOJI MAHARAJ NAGPUR UNVIVERSITY,
NAGPUR.2018-2019
Mrs. Snehal Rohadkar
Guide
Mrs. Rakshta Mankar
Principal
Mrs. Meghna Polkat
Head of
Department
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ACKNOWLEDGEMENT
Many individuals with whose cooperation and motivation I could complete this
research work should be thanked. Though not all of them directly helped me, they
stood by me in very trying times with numerous words of encouragement and much
needed moral support.
I am grateful to Mrs. Meghna Polkat H.O.D of textile, M.J. collage Nagpur from there
help, encouragement and other faculties extended while carrying out of the project.
First and foremost, I would like to thank my Project guide Prof. Snehal Rohadkar,
whose valuable guidance, suggestions and constructive criticism has helped me bring
this project to its present form.
Little room to write and so many people are there, I take this opportunity to thank all
faculty members and non-teaching staff members of M.J. collage, particularly during
the project work.
The support I received from all my family members and friends was valuable, without
their support it would not have been possible to come out with this project work. I am
thank full to them all.
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CONTENTS
01
02
03
04
05
INTRODUCTION
01 – 03
04 – 10
11 – 19
20 – 30
31 – 32
WOVEN FABRIC DESIGN &
STRUCTURE
COLOUR VISULAIZATION WOVEN
FABRICS
ADVANCE IN COLOR & WEAVE
DESIGN
CONCLUSION
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In the design of a fabric, luster and colour are two important aspects that can demand
attention from the textile designer as they have a considerable influence on the aesthetic
appeal of the fabrics. Lustre arises from the reflection of light from the surface of a textile
material. Colour is due to the reflection of light by the irregularities within fibres of a textile
material. In case of luster, the light reflection is regular, as if from a mirror and in case of
colour, the light reflection is diffuse, reducing luster, as in case of dyed materials.
The degree of luster of a textile material is influenced by the following factors:
(i) The characteristics of the fibres,
(ii) The manner of arrangement of fibres in the yarn
(iii) The type of weave
(iv) The type of finishing treatment.
Fibres such as Polyester, Viscose etc. have a smooth and uniform surface. They have the
ability to reflect light and thus give a very high luster. On the other hand irregular and
twisted fibres such cotton give very poor luster. Filament yarns with low twist present long
continuous surfaces to view, which give good reflection. In spun yarn composed of staple
fibres, the twist level is higher and thus the continuity of the surface is broken up and the
luster reduced. Some man made filaments, however, exhibit excessive luster or brilliance,
which is undesirable for the required uses and hence have to be delustred to a certain
extent. The nature of the weave too has a prominent influence on the luster. A weave such
as sateen has a longer float lengths of yarn in fabric and thus presents large continuous
areas of yarn to view. Similarly, finishes which are designed to enhance the luster increase
the uniformity and regularity of the cloth surface, e.g., calendaring, beetling etc., while
techniques intended to destroy luster achieve their aim by disturbing the surface, e.g.
raising. The observations of colour effects are purely subjective and, even when free from
physiological defects such as colour blindness no two people agree in their description of
every colour effect.
In woven designs from colored threads, a colored pattern is a consequence of two possible
arrangements where warp is over the weft or vice versa. Thus the primary elements of woven
fabric design are combination of weaves and blending of colors using such weaves. Weave is
the scheme or plan of interlacing the warp and weft yarns that produce the integrated fabric.
Weave relates specially to the build or structure of the fabric. Color is differently related to
effects of weave and form. The methods of utilization of color in woven textiles depend upon
the composition of the weave design to be woven and the structure parameters of the cloth.
Color and ornamentation in woven fabrics is imparted through the pre-determined
placement and interlacing of particular sequences of yarns. A solid color is produced by
employing the same color in warp and weft. On the other hand, different colors may be
combined to produce either a mixed or intermingled color effect in which the composite hue
appears as a solid color. Figured ornamentation is created through the selection of different
groups of colored yarns, placed in the warp and/or in the weft; while in certain patterns,
INTRODUCTION
1
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textural effects may be created entirely through the use of different values and closely
associated hues of certain colors. The figure is formed for the purpose of displaying different
pattern formations, adding dimension or color reinforcement and for enhancing a particular
motif.
Modern CAD systems provide a variety of design tools that are supported by standardized
color databases that allow simulation of weave structures on the computer monitor that
could be printed on paper. However, deviations of the color values of these simulations still
occur. Also, the color on fully flat fabric simulations on paper or computer screen is two-
dimensional that differs from the real three-dimensional nature of fabrics and yarns.
In textile wet processing, the uses of colorimetry systems and associated software have
proven their worth over the years, in objective estimation of color, and have minimized
misunderstandings between textile manufacturers and their customers. However, color
communication within textile design is largely a subjective process. Recent experimental
studies (Osaki 2002; Dimitrovski & Gabrijelcic 2001, 2002, 2004) have revealed that the use
of colorimetry has helped to achieve better reproducibility and accuracy in the shade
matching of textiles products. Colorimetry is, however, less used when fabrics are made from
colored
yarns than when yarns and fabrics are dyed to a solid color, or are printed. Recent research
work (Mathur et. al. 2005, 2008, 2009 and 2011) provided a model that involves colorimetry
for color prediction and is discussed briefly in section 4.
Several measuring and imaging systems are now available commercially that can record
colorimetric data and convert these data into visual images. Hence, the designer can generate
a numerical color specification that can be visualized accurately on a suitably calibrated
monitor. Recent advances in color curve generation and image processing provide
opportunities for additional improvements in the areas of collaborative color development,
color marketing, and color prediction in multi-step processes. Contemporary techniques of
computer-aided fabric design offer new possibilities for using colorimetry in weaving practice.
Along with the fundamental description of weave and color relationship, and recent advances
in woven fabric design, this chapter also includes the research models developed to quantify
the color proportion and color values, in effort to eliminate the expensive and time consuming
process of prototyping and color matching in woven fabric design.
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4
WOVEN FABRIC
DESIGN AND
STRUCTURE
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This section introduces the reader to the basic knowledge of woven fabrics design and
structure and the concept on how colored patterns are created using colored yarns. It sets
the stage for the next sections that deal with objective evaluation of color in woven
structures.
Woven fabrics are formed by interlacing two orthogonal sets of yarns; warp yarns that are
vertically arranged and weft yarns that are horizontally placed. While all weave structures are
created from a binary system (that is a warp yarn is over or under a weft yarn at the crossover
areas), infinite number of weaves can be formed. The distribution of interlacement is known
as weave design or pattern. There are three types of weaves that are known as basic weaves,
which include plain weave (the simplest and smallest repeat size possible; 2 warp yarns x 2
weft yarns) and its derivatives, twill weaves and their derivatives, and satin/sateen weaves
and their derivatives. These basic weaves are characterized by their simplicity, small size, ease
of formation, and recognition. However, they form the base for creating any
complex/intricate structures (such as multi-layer fabrics and pile weave structures) and
weaves with extremely large patterns that are known as Jacquard designs. Figures 1-3 show
examples of basic weaves. More on the rules to construct basic weaves and their derivatives
can be found in Seyam 2001.
Fig. 1. Plain weave
WOVEN FABRIC DESIGN &
STRUCTURE
2
Fig. 2. Example of twill weave (2x2 Right Hand Twill weave)
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Fig. 3. Example of sateen weave (5-Harness Sateen Weave)
Figures 1-3 depict two methods of presenting weaves namely flat view and weave design.
While the flat view presentation provides better understanding in regards to the warp and
filling yarn interlacing, it takes time to draw especially for large size repeats. The weave
design presentation was created to communicate in a much simpler and easy to draw weave
illustration using weave design paper (squared paper). In the weave design presentation the
spaces between yarns are eliminated and only the squares where warp yarns are over the
weft yarns are shown, which is reasonable since in most of woven fabrics the yarns cover
most of the fabric surface. Any color or marks (such X, /, or , etc.) can be used to indicate
where a warp yarn is over a weft yarn. The squares that are left blank indicate otherwise.
2.1 Color/weave relationship
Figure 4 shows another illustration of the weaves of Figure 1-3. In Figure 4 all the squares of
the weave design presentations are painted using the color of warp and weft yarns (red and
blue). This is known as color effect presentation. It should be pointed out that a square in
the design paper represents extremely small size area in the woven cloth. The colors of
Figure 4 will be perceived by human eye as a mixture of two colors with different ratios.
Fig. 4. Color effects
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Fig. 5. Color simulation of the plain weave of Figure 1
Fig. 6. Color simulation of the sateen weave of Figure 3
Thus, the use of colored warp and weft yarns combined with the weave structures permit
the development of striking patterns. For a given pattern with multi-color, a color can be
strategically placed in the pattern by merely using the binary system of warp and weft
interlacing. The desired color of a yarn appears when the yarn is over the crossing yarns for
a desired length and small or large area if several yarns are used. Moreover, numerous
mixtures of colors to produce other colors can be obtained from few colors of the warp and
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weft yarns through proper weave interlacing. Figures 5 and 6 are two examples of such
mixtures. They were produced using many repeats in warp and weft directions, thread
count close to real cloth, and assuming there are no spaces between the yarns, which is
reasonable assumption for most woven fabrics. Figure 5 is the color simulation produced
from red warp yarns and blue weft yarns and plain weave of Figure 4(a). While the color
simulation of Figure 5 is produced from red warp yarns and blue weft yarns woven in sateen
of Figure 4(c). These two examples indicate that numerous purple colors can be produced
from only two colors (red and blue). Using this concept striking patterns can be created
using few colors in warp and weft directions such as the Jacquard design of Figure 7.
Pattern is courtesy of Manual Woodworkers and Weavers, Hendersonville, N.C., USA
Fig. 7. Color simulation of Jacquard faric
2.2 CAD and woven fabric design
Designing fabrics is a creative/technical process that is dependent upon the ability of the
textile designer to combine aesthetic sensibility with a strong knowledge of the technology
of materials and fabric production machinery. Most Dobby and Jacquard fabrics producers’
facilities are now equipped with Computer Aided Textile Design systems. In the pre-
computer era, the designing process was done in the following manner: (a) a piece of
artwork was created on paper, (b) the artwork was then rendered as a scaled grid (known as
squared paper or design paper), whose columns and rows represented warp and weft yarns,
respectively, (c) weaves were then assigned to specific areas to represent the original
pattern, and (d) a technician then punched cards, direct from this technical design layout, in
which each card represent one pick of the actual fabric.
Computers have been utilized in woven textile design for almost 25 years, and this has
revolutionized the entire design process. They have revolutionized the entire thought-
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process from the initial artwork to final production. CAD systems in woven designing
operate in a series of basic steps. The first step is that of digitizing the artwork. This feature
allows the designer to see the artwork on a computer monitor by scanning the original piece
or creating a design using the CAD system drawing tools directly. This is generally done in 8-
bit format (256 colors) and allows the designer to modify patterns and reduce the number
of colors to a manageable number as he/she wishes. The second step is fabric designing, in
which the artwork image data is transformed (i.e. the grid system, above) into weaving
information for fabric production. Weave allocation is the third step, in which information
from the artwork image can be converted into a woven fabric. The designer created the
appropriate weave structure or chooses one (from a weave library) to match the desired
color, shape or texture in the artwork. This part of the program also helps the designer to
see a simulation of the final fabric on the display monitor. By looking at the preview, the
designer can easily modify the design, and can change the weaves to recolor the design as
required. All these developments have greatly increased the ease of woven fabric designing.
It is now possible to perform the entire process on a personal computer, and then transfer
the ready-to-weave file (electronic punch-card file) via the internet, direct to the dobby or
Jacquard controller at the loom, or to some interim storage area.
Textile CAD/CAM systems are mainly modular in structure and, in addition to covering yarn
and fabric design may also include very realistic 3D simulation packages. A complete
automated process with immediate response to the customer’s demand seems to be a
reality in the near future with these systems (Dolezal & Mateja 1995; Bojic 1999; Dimitrovski
& Bojic 1999). Moreover, developments of powerful modem systems and electronic controls
have brought the weaving machine into the design studio. This evolution has, in turn, given
an entirely new meaning to the term Quick Response.
The impetus for use of CAD in the textile industry was to improve efficiency in the
production process. Initial textile designing software packages were mainly derived from
graphic design software, without putting much emphasis upon the underlying fabric
structures. CAD systems have evolved, however, by considering the designing process and
technical limitations. These systems are now extensions of creative expression which
comply with technical requirements (Doctor 1997). Numerous descriptions of this process
exist within the computer environment (Lourie 1969, 1973; Lourie & Bonin 1968; Lourie &
Lornzo 1966) addressing, algorithmically, the problems that arise when one attempts to
harmonize visual pattern with the notational point paper diagrams of those used for warp
and weft interlacing.
Innovation in the field of textile design CAD systems for woven fabrics has provided the
opportunity to design intricate fabrics with the use of a variety of tools. There is also the
possibility of seeing the resultant fabric on a computer monitor that gives the visualization
of real fabric prior to weaving. There is constant improvement and development in the CAD
system to develop several design features (CAD tools) to keep pace with new market
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demands. At ITMA 2003, 40 companies exhibited CAD systems. Most of the weaving
machinery companies showed CAD systems as an accessory. Many CAD companies (UVOD,
Fractal Graphics, Yxendis, ScotWeave, EAT, NedGraphics, Pointcarré, Mucad, Informatical
Textil, Booria CAD/CAM systems, Arahne etc.) showed constant improvement in the quality
of CAD systems such as, easy-to-use software modules, flexibility of changing constructional
parameters, speed of defining technical data and enhanced visualization of fabric structures
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COLOR
VISUALIZATION
IN WOVEN
FABRIC
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In pre-colored yarn or fabric, when light falls on the colorants (dyes or pigments), the white
light is broken into its component wavelengths. Depending upon the particular molecular
structure of a colorant and surface, light may be reflected back to the viewer, absorbed into
the molecular surface, scattered by the molecular surface, transmitted through the surface
or be subjected to some combination of reflection, absorption and transmission. One of the
three processes always dominates; however, this in turn produces color effects (Lambert,
Staepelaere & Fry 1986; Menz 1998). The color effect of perceived color is a consequence of
three types of color mixing principles:
a. Additive Color mixing is a basic phenomenon for color perception, which involves addition
of wavelengths of light to create higher-value colors. The broadest bands of color seen in
the visible spectrum are those belonging to red-orange, green and blue-violet, known as
Primaries. When all these colors are projected and overlapped, their specific wavelength
mix together and produce white light (Figure 8). Magenta, cyan and yellow are known as
Secondary colors where only two colors overlaps and their respective wavelengths add
together.
Fig. 8. Additive color mixing (McDonald 1997)
b. Subtractive Color Mixing is created by the addition of pigment materials such as dyes,
inks, and paints that remove reflecting wavelengths from light from each other, allowing us
to see new color. When the pigment primaries that are cyan, magenta and yellow are mixed
together, they culminate in black (Figure 9).
Fig. 9. Subtractive Color Mixing (McDonald 1997)
COLOR VISUALIZATION IN
WOVEN FABRIC
3
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c. Optical Color Mixing is also known as Partitive Color Mixing because optical mixtures
combine additive and subtractive color mixing phenomenon. This is an effective method of
creating mixtures that appear to vibrate and mix at particular distances when small areas of
color are juxtaposed as shown in Figure 10.
Fig. 10. The Optical mixture (c) is a result of weaving the yarn used in sample (a) with yarn
used in sample (b) (Lambert, Staepelaere & Fry 1986)
Partitive color achieved in woven fabrics does not follow the same rules as the other cases
(such as in additive and subtractive color mixing), presumably because the individual yarns
are not completely opaque and moreover the fabrics are made from blends of several
colored yarns with different weave effects.
Furthermore, the relation between the color values of different colors and their size must
be carefully considered. When two colors are in juxtaposition with each other, each takes
on the complement of its neighbor. This is known as law of ‘Simultaneous Contrast’. In
woven fabrics, the appearance of the color is a consequence of light reflected back from
different areas of color surface of the yarns involved in the fabric structure. Looking at the
color wheel (Figure 11), if color values of warp and weft are taken into account, behavior of
the color contrast and harmony can be well understood.
Complementary colors lie on the opposite sides of the color circle, and their sum of
reflected light gives an unsaturated color, which can be observed as a grayish hue on the
fabric. On the other hand, the close positioning of two harmonic colors gives similar color
value.
In woven designs, in case where fabric is made of multi-colored yarns, the final visualized
color is a contribution of each color component present on the surface of the structure.
Individual color components are blended and seen as one solid color. This blending of color
is governed by the above mentioned color mixing principles. Blending of fibers has been
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very well studied in the past (Pierce 1997, Burlone 1990, Friele 1965, Miller 1979, Guthrie
1962, Burlone 1983, Walowit 1987, 1988, Burlone 1984, Reed et. al. 2004, Amisharhi &
Pailthorpe 1994), but very few literatures have discussed the blending of yarns in fabric
structure (Mathur 2007).
(a) Color wheel
Fig. 11. Optical Color Mixing (Richard & Struve 2005)
(b) OPTICAL COLOR MIXING (ANALOGOUS)
juxtaposition of small areas of analogous
colors forces viewer to mix them optically,
blend on a very small scale creating a
(c) OPTICAL COLOR MIXING (COMPLIMENT)
juxtaposition of small areas of complimentary
colors forces viewer to mix them optically,
cancelling each other out
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Each colour creates a certain impression on the mind of the observer. Red appears as a
brilliant and cheerful colour, and gives the impression of warmth. It is a very powerful colour
and appears to advance towards the observer. Blue is a cold colour and appears to recede
from the eye. Yellow is a very luminous and vivid colour and conveys the idea of purity. The
qualities of the secondary colours are somewhat intermediate between the primary colours of
which they are composed. Thus orange is a very strong colour and possesses warmth and
brightness, but it is not so intense as yellow. Green is a retiring and rather cold colour, but
appears cheerful and fresh. Purple is a beautiful rich and deep colour, and for bloom and
softness is unsurpassed. The primary and secondary colours are too strong and assertive to be
used in large quantities in their pure form except for very special purposes. They are chiefly
employed in comparatively small spaces for the purposee of imparting brightness and
freshness to fabrics. Their strength is greatly reduced by mixing with black or white when
they are used in large quantities as ground shades.
Modification of colours
Modification of pigment colours can be done in the following ways
(a) By mixing with a different colour
(b) By mixing a colour with black
(c) By mixing a colour with white.
A change in hue results by mixing two different colours. For example, scarlet colour is obtained by adding
a small quantity of yellow colour to red. The relative proportions of the colours mixed determine the
change in the degree of hue. For example, if red predominates in a mixture of red and blue the hue is
reddish violet.
Important definition relating to colour theory
Tone
It results from mixing a colour with white or black
Tint
It results from mixing a colour with white in different proportions. It is a tone which is lighter.
Shade
It results from mixing a colour with black in different proportions. It is a tone which is darker.
Coloured grey
These are certain neutral or broken colours which result from mixing a normal colour with both black
and white in varying proportions.
Mode shade
It is a broken colour in which a certain hue predominates.
Monochromatic contrasts
These are contrasts in which two tones of the same colour are combined.
Example : Two shades of red or three tints of blue. Some of these contrasts in softer version are
suitable for over coatings, suitings and costumes.
Polychromatic contrasts
These are contrasts in which two or more different colours are combined which may be alike or
different in tone.
Example : Light green and light blue, light green and dark red.
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Style
A style is one which partakes of both classes of contrast when a ground pattern, consisting of different
tones of the same colour, has bright threads of another colour introduced upon it at intervals for the
purpose of improving the effect.
Successive contrast
In successive contrast the colours are such a distance apart that one is perceived after the other.
Simultaneous contrast
In simultaneous contrast the colours are placed in juxtaposition so that both are seen at the same time.
Contrast of hue
In contrast of hue each colour influences its heighbour.
Example : Dark blue and light blue and when dark and light colours are placed together - dark blue
and light green. The dark colour, by contrast, makes the light colour appear lighter than it actually is,
while the light colour makes the dark colour appear darker than it is.
Colour harmony
It results from any combination of hues that is pleasing and gives full satisfaction to the observer.
Harmony of analogy
There are two ways of producing harmony of analogy :
(a) By the combination of tones of the same colour that do not differ widely from each other.
(b) By the combination of hues which are closely related and are equal or nearly equal in depth of
tone.
Example : Different tints of red, or shades of blue when combined, yield a harmony of analogy of
tone, if the difference between them is not too marked.
Tone shaded effects
These are produced by combining a series of scale of tones of a colour which are so graded and arranged
as to run impercetably one into other.
Harmony of analogy of tone
This results from combination of different tints or shades of a colour, if the difference between them is
not too marked.
Harmony of contrast
There are two ways of producing a harmony of contrast
(a) By the combination of widely different tones of the same colour.
(b) By the combination of unlike colours
An example of ‘harmony of contrast of tone’ is a pleasing combination of 2 tones of blue marked by
an interval in between.
An example of ‘harmony of contrast of hue’ is the harmonious union of red and green. Harmonies of
analogy are of chief value in producing quiet effects. Harmonies of contrast are useful when clear and
smart effects are required.
Harmony of succession or gradation of hue
It is one in which there is a succession of hues that pass gradually one into the other. The colour spectrum
is a typical example.
Divisional colours
These are colours which are introduced to separate two contrast colours, as other wise the colours
appear blurred and confused at their joining. By using divisional colours, the strength of the contrast is
thereby reduced, and the colours are made to appear clear and precise
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Method of colour Application
The following are the various methods of producing colour application that give a mixed colour effect:
(a) Combination of two or more types of fibres and dyeing the fabric made out of them.
(b) Printing of the spun yarn in different colours.
(c) Using differently dyed yarns which are arranged alternately, and weaving them in an irregular or
broken manner.
(d) Addition of small dyed tufts of fibres at some stage prior to spinning. This results in a spotted
colour effect on the yarn.
(e) Fibres of different colours can be blended to produce a mixture yarn.
(f) Twisting together differently coloured threads to produce fancy type yarns.
(g) By printing slivers in strands of different colours ‘melange’ yarns can be produced
Classification of Colour and weave effect
The orders of colouring the threads can be classified as follows:
(a) Simple warping and simple wefting
(b) Simple warping and compound wefting
(c) Simple wefting and compound warping
(d) Compound warping and compound wefting
In the first and the last the order of warping may be the same, or different from the order of wefting.
Simple stripe and check patterns may be applied to each order of colouring.
3.1 Color visualization in CAD systems
In computer-aided design, there is a popular acronym called “wysiwyg”, which means
“what you see is what you get”. Unfortunately, the wysiwyg concept often fails when
dealing with the issue of color and reproducing color for different output devices. For
example, it is difficult to match three different fabrics, all of which have different fiber
content, because each fiber requires a different dye formulation. The same concept
holds true in the world of computer generated color. Each color device used in CAD and
production, including monitors, desktop printers, and commercial four-color process
printers, have unique definitions and limitations for color by virtue of their own unique
technology (Ross 2004).
Hoskins et al. (1983, 1985) developed an algorithm to analyze the color of woven
structures. Since size of the design and restricted color sets were the limitation for the
industry requirements, this algorithm was developed to provide the possibility of
capturing any kind of image by the system. The system could then provide important
elements of color in the image without compromising the storage requirements or
degrading the system’s response time. Rich (1986) discussed the basic colorimetry of
CRT (Cathode Ray Tube) displays, both instrumental and visual, as applied to textile
design systems. His paper emphasized CRT-based graphical displays to generate colored
images. He also suggested some technical aspects for accurate and repeatable
representation of the weave and color of the textile on display. Similarly, Takatera and
Shinohara (1988) developed a search algorithm to determine the color-ordering of the
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yarns and weave, to obtain a given pattern of color-and-weave effect. Dawson (2002)
examined color-and-weave effects with small repeat sizes. He studied the effects of yarn
color sequences over several weave repeats. Grundler and Rolich (2003) proposed an
evolution algorithm to combine the weave and color, in order to have a predetermined
idea of the appearance of the fabric to be produced. Based on the algorithm, software
was then developed to access different fabric patterns and allowed the creation of new
patterns, based on the user’s choice.
Colors displayed via computer monitors cannot be specified independently. Therefore,
color is considered as one of the major aspects of a user-centered design process. Most
current CAD systems use uncalibrated color and, in consequence, designers are unable
to define or communicate accurately the color of the image-design effect that they
produce on the computer screen. A system with calibrated colors gives precise
definitions for all colors seen. The numerical specifications for colors used in current
CAD systems are expressed in terms of red, green, and blue (RGB) or hue, value, and
saturation (HVS) combinations. Importantly, the CIE system of color specification (via
tristimulus values, XYZ) is independent of any specific reproduction system and is widely
used to specify color in textile manufacturing (Polton & Porat 1992).
The color issue represents not only one of the most frustrating aspects of CAD, but the
area with the most rapidly advancing technology. A color management system, or CMS
can be used to create color for specific output devices. Theoretically, this allows for
more consistent and accurate color results between different output devices. A CMS
works in the background and translates colors based upon pre-defined color profiles for
specific output devices, allowing for more consistent color viewing and output. CMS’s
provide new possibilities for accurate color communication, but they cannot be
considered an ultimate solution (Ross 2004).
Since the introduction of spectral-based imaging systems some years ago, algorithmic
data communication of color standard and production ‘submits’, between retailers and
suppliers, has proven to be one of the primary economic applications of the technology.
Recent advances in color curve generation and image processing provide opportunities
for additional improvements in areas of collaborative color development, color
marketing, and color prediction in multi-step. At the same time, there are other aspects
of imaging technology that have strong economical implications in other areas besides
color communication. The other applications are derived from what is considered the
very heart of such a system – the spectral base for color. Contrary to most CAD type
systems, the input and output channels are spectral reflectance values either measured
or generated and are largely device and illuminant independent. The spectral data are
by far the most basic characterization of an object’s color. From these spectral values,
we derive all the other higher level output forms such as colorimetric values (X, Y, Z, L*,
a*, b*, C*, H*), output to the monitor in calibrated color (R, G, B), and to the calibrated
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printer in C, M, Y, K. By combining the spectral base, colorimetric functions, and an
image processor, the color imaging system is a powerful tool for color management
(Randall 2004).
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ADVANCES IN
COLOR &
WEAVE DESIGN
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Recently, a number of technological advancements have been introduced by weaving
machine producers, such as: high speed weaving, higher levels of automation, new
shedding concepts, automatic (on the fly) pattern change, and filling color selection.
Along with the advances in weaving, significant development has also occurred in the
field of CAD systems, which enables automation in the design process. Despite this
automation, the process of assigning weaves/colors is still done by the designers or CAD
operator, which therefore requires physical sampling prior to production. This section
includes the recent research work done to automate the process of assigning
weaves/colors in order to reduce or even eliminate the need for physical sampling and
to assist woven fabric designers in the creation of pictorial fabrics that are a very close
match to the original “artwork” or target.
Fig. 12. Cover factor calculation for a Plain weave fabric
In woven fabrics, which are highly textured, various patterns become visible through
their different structures. The color of such patterns also depends upon the color of the
yarns involved, their combinations and different structures on the pattern surface. The
final visible color on the fabric surface is mainly due to the contribution of fabric
covering properties, namely optical cover and geometric cover (Lord 1973; Adanur 2001,
Peirce 1937). The optical cover properties are defined as the reflection and scattering of
the incident light by the fabric surface and are a function of the fiber material and fabric
surface. Geometric cover (characterized by fabric cover factor) is defined as the area of
fabric actually covered by fibers and yarns. Fabric cover factor is the ratio of surface area
actually covered by yarns, to the total fabric surface area (shown in Figure 12).
ADVANCES IN COLOR
& WEAVE DESIGN
4
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EFFECT PRODUCED BY SIMPLE COLOUR AND WEAVE COMBINATION
In designing simple colour and weave combinations the arrangement of the threads as to
colour may be regular (e.g.: 2 dark, 2 light or 4 dark, 4 medium, 4 light), or irregular (e.g.: 3
dark, 1 light, 3 dark, 2 medium, 1 light). By arranging the weft in a different order from the
warp, attractive effects can be brought out.
By applying simple weaves to simple orders of colouring the following effects can be
produced
(a) Continuous line effects
(b) Hound tooth patterns
(c) Bird’s eye and spot effects
(d) Step patterns
(e) Hairlines
(f) All over patterns.
(a) Continuous line effects
The figure above shows the typical line effect produced by colouring the 2 and 2 twill in the order of
2 dark, 2 light. The same effect can be produced in different ways such as symmetrical zig zag, serrated
etc.
(b) Hound tooth patterns
In the above design, the order of colouring
is 4 dark, 4 light in warp and weft, and the
weave 2 and 2 twill. Different variations
are possible by changing the weave and
order of colouring.
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(c) Bird’s eye and spot effects
Spot patterns can be produced by simple orders of warping and wefting. A spot is formed where a
warp colour is intersected by the same colour of weft. Thus the desirable pattern can be produced by
arranging the warp or weft floats suitably at places where different colours intersect.
(d) Step patterns
The above design shows a 2 and 2 twill coloured 1 dark and 1 light. Similar effects can be produced
with different twills as 3 and 3, 4 and 4 etc. with different orders of colouring.
(e) Hairlines
Weaves such as plain, hopsack, satinete etc., can be used with different colouring orders. Figure
above shows an effect produced by using a 4-thread twill (3/1) and choosing order of colouring 1 dark
and 4 light both warp and weft way.
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(f) All over patterns.
In these patterns, the colour effect runs in an unbroken pattern over the surface of the cloth. All over
effects can be constructed by suitably arranging the repeat of the colour plan and the repeat of the weave
in a such a way that two or more repeats of a weave are required to produce a complete repeat of the
pattern.
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Methods of producing variety of effect in the same weave
& colouring
An important factor to note in designing colour & weave effects is that different patterns can
usually be obtained in one order of colouring & one weave by changing their relative positions.
This is illustrated by the patterns represented in figures below. Each pattern, A to D in figures is
produced by the combination of a 4-&-4 order of warping & wefting with a 2-&-2 hopsack weave.
There are two ways in which the change of effect may be brought about:
As shown in figure I, the warp & weft threads may be arranged as to colour in the same manner
throughout (i.e. 4 dark, 4 light), but with the weave placed in a different position in each case.
Figure I
A
Combination of a 4-&-4 order of warping
& wefting with a 2-&-2 hopsack weave
B
C
D
As shown in figure II the weave may be placed in the same position throughout, but with
the colour pattern commencing in a different manner in each case. In the latter method
either the warp, or the weft, or both the warp & the weft colours may be changed in
position.
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Figure II
It will be noted that the difference of effect in some cases is very slight, one-half of
the patterns when turned over being simply duplicates of the other half the example,
however, is illustrative of the necessity in weaving of always retaining the same
relation between the colouring & the weave throughout the length of the cloth. In
subsequent examples it is shown that the change of effect thus produced can be
made use of, not only in designing small patterns, but also in the economical
production of stripe & check designs in very great variety.
A
combination of a 4-&-4 order of warping
B
C
D
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4.1 Color prediction model
Recent research (Mathur et. al. 2005, 2008, and 2009) provided a method to calculate the
contribution of each color in an area of a pattern through numerical examples. The method
utilized in this research is tedious, especially in the case of large patterns with numerous
warp and filling yarns, colors, and weaves. Additionally, the method cannot be programmed
to enable the automatic calculations of color contribution from basic design parameters. In
this section, a generalized model is discussed briefly that enables the user of a computer
simulation to input basic design parameters. The basic parameters used in the generalized
model are warp and filling yarns linear densities, warp and pick densities, weave, color
arrangements of warp and filling yarns, and color of the background. With proper computer
programming of the model, a suitable color mixing equation (Mathur 2007), and databases
of yarns colors, yarns, and weave, the process of color/weave selection could be automated
without operator/designer intervention and without the need to weave color gamut (Seyam
and Mathur 2008).
Figure 13 demonstrate an example to provide a clear understanding of the parameters
involved the modeling and the contribution of each color component. Figure 13 is a flat view
of 2x2 L.H. Twill with various warp and filling colored yarns (warp color arrangement: 1
purple, 1 light blue, 1 red and filling color arrangement: 1 dark blue, 1 green, 1 black).
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Fig. 14. a) Current/Traditional Design Process - Weave selection and sample matching still
require the intervention of designer, who works from color gamut (blanket)
Fig. 14. b) Implementation of the Model in the scheme of the design process
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Fig. 15. Implementation of the Model in the scheme of design of patterned woven fabric
(Seyam and Mathur 2008)
The color values obtained from these color equations (Equations 7 and 8) were analyzed
statistically to validate the predicted color using the CIELAB ∆ECMC(2:1) color difference
equation (McDonald 1997). Also, extensive visual assessment experiments were designed
and conducted for assessing the visual difference between the predicted and the actual
color appearance of the woven structure. The results obtained from statistical analysis and
visual assessment are reported elsewhere (Mathur et. al. 2008) The equations show how
the geometric model and color model are combined to obtain the final color prediction in an
objective way so the woven fabric color for each part of the design can be calculated using
computer programming to automate the process of weave selection, which is currently
(traditionally) decided subjectively by the designer which leads to more trials, high cost and
long lead time to achieve the final target fabric (Figure 14a and b). Figure 14 a shows that
three trials were conducted to reach to the target artwork while Figure 14 b indicates the
Benefit of employing geometric and color models to automate the process of weave (color)
selection. The schematic flow of the design process using the model is illustrated in Figure
15. The process starts from creating artwork and measuring color attributes (defined in
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CIELAB color space (McDonald 1997)) for each color in the artwork. The computer
simulation of the model allows the user to enter the design parameters. Next, the
developed geometrical model calculates the contribution of each color and in combination
with the color mixing equation, the final color of an area in the pattern can be obtained. The
calculated color attributes are compared to the measured from the artwork. The difference
of color attributes between the measured and calculated is checked. If the difference is
within the tolerance, the program reports output that include the color attributes for
calculated and actual, color arrangement, specific weaves within the classified weaves.
In case if the color differences are out of tolerance, the program reports to the user and
suggests possible changes to the input parameters. This iteration continues until a
reasonable match for each color in the artwork is achieved.
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Color blending in woven fabrics is defined as the process of mixing
color by combining different colored yarn components to produce a
homogenous color appearance. Different colored yarns are mixed in
certain proportion to obtain a required color. The final color is a
function of the constructional parameters that manifest changes in
the area of each yarn on the surface. The colorimetric data of the
weave structures can be calculated by using the combined effect of
the two aspects of fabric covering power, the optical (reflectance) and
the geometric. The geometric model is discussed in this chapter
combined with suitable color mixing model can be used to calculate
colorimetric attributes on the surface of the woven fabric. These
calculations can be easily programmed and the process of assigning
weaves/colors can now be automated and therefore the subjective
intervention of the designer is no longer needed. This will help in
eliminating the need for physical sampling prior to production and the
subjective opinions as the color/weave selection will be done
automatically by computer based on the colorimetric values that are
very close match to the original artwork.
CONCLUSION
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Adanur, S. 2001, Handbook of Weaving, Technomic Publishing Co., USA.
Amisharhi, S. & Pailthorpe, M.T. 1994, "Applying the Kubelka-Munk Equation to Explain
the color of blends prepared from pre-colored fibers", Textile Research Journal, vol. 64, no.
6, pp. 357-364.
Berns, R.S. 2000, Billmeyer and Saltzman’s Principles of Color Technology, 3rd edn, John
Wiley & Sons Inc., New York, USA. Bojic, M.B. 1999, "CAD/CAM systems for Dobby and
Jacquard Weaving", Tekstilec, vol. 42, pp. 77.
Burlone, D. 1984, "Theoritical and Practical aspects of selected fiber blend color-formulation
functions", Color Research and Application, vol. 9, no. 4, pp. 213-219.
Burlone, D. 1983, "Formulation of Blends of Precolored Nylon Fibers", Color Research and
Application, vol. 8, no. 2, pp. 114-120.
Burlone, D.A. 1990, "Effect of Fiber Translucency on the Color of Blends of Precolored
Fibers", Textile Research Journal, vol. 60, pp. 162-166.
Dawson, R.M. 2002, "Color and Weave effects with some small weave repeat sizes", Textile
Research Journal, vol. 72, no. 10, pp. 854-863.
Dimitrovski, K. & Gabrijelcic, H. 2004, "Corrections of color values of woven fabrics using
REFERENCE
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